Technical Field
The present invention relates to a lens driving apparatus, and more particularly, to a lens driving apparatus having an insert molded structure.
Description of Related Art
Electromagnetic actuators have been widely used in driving lenses. Referring to FIG. 1, a lens driving apparatus equipped with such an electromagnetic actuator generally includes (but not limited to the following components), in a sequential order along an image formation direction, a housing 10, a lens holder 11, a coil 12, a plurality of magnets 13, an upper leaf spring 14, a lower leaf spring 15 and a base 16, which are assembled substantially along a Z axis (optical axis) direction. After the above components have been assembled, the housing 10 covers the base 16 in a manner such that an accommodation space is defined between the housing 10 and the base 16 to receive therein the remaining components 11-15. The lens holder 11 is configured to hold a lens (not shown). The coil 12 is installed onto an outer circumference of the lens holder 11 and becomes a part of the lens holder 11. The upper leaf spring 14 and the lower leaf spring 15, which is electrically connected to the wires at two ends of the coil 12, are disposed in the accommodation space to sandwich therebetween the lens holder 11. The plurality of magnets 13 are arranged around and spaced apart from the coil 12. After the above components have been assembled, the electromagnetic induction generated when an electric current is supplied to the coil 12 will cause the lens holder 11 to move substantially in the Z axis direction.
Generally, some of the above components are connected with adhesives. Connections among these components may break under intensive operation, resulting in the loss of control in driving the lens. For example, a portion of the lower leaf spring 15 is securely connected to the lens holder 11 while another portion of the lower leaf spring 15 is securely connected to the base 16. In this lens driving apparatus, the lower leaf spring 15 mainly serves to perform electric conduction to transmit control signals from the base 16 to the coil 12 of the lens holder 11. Once the above connections break, the lower leaf spring 15 may be in weak contact with the lens holder 11 or the base 16, causing an interruption of the circuit.
Therefore, there is a need in the art for a lens driving apparatus comprising components with improved mechanical functionality and reliability.